The present invention relates to a camera in which a cartridge is used, wherein a photographic film is loaded in the cartridge, and a bar code, which can be read from the outside of the cartridge, and a lock mechanism of a spool are provided in the cartridge.
As a prior art with respect to a cartridge in which a film is loaded, and a circular bar code readable from the outside thereof and a lock mechanism of a spool are provided, for example, the following has been disclosed: Japanese Patent Publication Open to Public Inspection NO. 237043/1992.
On the cartridge in this publication, a circular bar code plate, on which a bar code is written, is provided. With this bar code, the film sensitivity, and the number of exposable frames are displayed. This bar code plate is rotated with the spool around which the film is wound. In order to memorize information of the bar code in a camera, automatic film loading is conducted in the camera after the cartridge has been loaded in the camera, and the information is stored in the camera until the first frame of the film is wound. However, when the film of the cartridge is automatically loaded, since, initially, the spool provided in the cartridge is rotated so that the film is fed, the rotation of the bar code plate is slow. However, after the leading edge of the film, which was drawn out, has been engaged with a winding reel, the film is wound up by the reel. Accordingly, the rotation of the bar code plate is faster. As described above, since the number of rotations is changed within a short period of time, reading errors easily occur. When information such as a film sensitivity and the number of exposable frames are stored erroneously, serious problems occur.
Further, in this publication, a prevention mechanism of cartridge loading into the camera has been disclosed so that exposed film is not erroneously used again. However, since this mechanism is a mechanical, there is a possibility that problems occur, and cost is raised by this mechanism.
Still further, the spool lock mechanism has been disclosed in the publication. However, the relationship between the rotational portion of the spool and a driving shaft of the camera, or the relationship between the lock mechanism and a release pin of the camera, is not specifically regulated. Accordingly, there are problems in which the lock is inadvertently released during the cartridge loading operation, or cartridge removal operation, and the spool is rotated, so that the bar code plate is also rotated.
In view of the foregoing problems of the conventional technology, the present invention accomplishes the following 3 objectives.
1 A camera which positively reads out the film information on the bar code provided on the cartridge.
2 A camera in which film re-feeding can be prevented when an exposed cartridge is erroneously loaded in the camera.
3 A camera in which a lock can not inadvertently be released during the cartridge loading or cartridge removal.